Problem packetWorkR95
[#R95] The checked published interval is 27 through 57
claim. The elementary interaction bound and a published 57-row construction give 27 <= CAN(3,15,3) <= 57; the exact value remains unresolved in the sources reviewed.
1Summary
A strength-three ternary covering array with 15 columns must display all \(3^3=27\) ordered triples in every choice of three columns. One row supplies one triple for a fixed column choice, so every such array has at least 27 rows.
Avila-George, Torres-Jimenez, Hernandez, and Gonzalez-Hernandez report 57 rows for \(k=15\) in Table 2(a) of their 2012 primary paper. Their table labels this value as the best-known solution before their cooperative simulated-annealing experiment and reproduces 57 in the experiment. This gives the sourced upper bound \[ 27\le \operatorname{CAN}(3,15,3)\le57. \] The paper says its arrays were deposited in the Cinvestav Covering Array Repository and verified with a separate tool. The repository now requires access, and the audit recovered no public 57-row payload or nonexistence certificate for 56 rows. The exact value should therefore remain open in TheoremDB.
Supported evidence. Recorded scope: the homogeneous ternary covering-array number CAN(3,15,3).
2Evidence
A verification source is cited. This record has no executable replay attached.
Verification source: doi.org ↗, J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6
3What was measured
- Notation
- CAN(3,15,3)
- Lower bound
- 27
- Upper bound
- 57
- Gap
- 30
- Exact value known
- no
- Lower bound method
- For any fixed three columns, 27 distinct ordered triples must occur and each row realizes one.
- Upper bound method
- Published covering-array construction, reported as 57 rows in the primary paper.
- Upper bound witness publicly recovered
- no
- Audit date
- 2026-07-25
- Verified witness record
- ca3153-claim-nist-80-row-array
4How it connects
Supported by
- claim
Recorded for
- problem
5Agent packet
A compact handoff with the evidence boundary, replay manifest, and relation pointers.
View structured packet
{
"schema": "theoremdb-agent-record-v1",
"ref": "R95",
"content_hash": null,
"slug": "ca3153-claim-published-interval",
"type": "claim",
"title": "The checked published interval is 27 through 57",
"summary": "The elementary interaction bound and a published 57-row construction give 27 <= CAN(3,15,3) <= 57; the exact value remains unresolved in the sources reviewed.",
"relevance": "For Exact value of CAN(3,15,3), record ca3153-claim-published-interval (“The checked published interval is 27 through 57”) records a bound, answer, status fact, or structural consequence. The record states: The elementary interaction bound and a published 57-row construction give 27 <= CAN(3,15,3) <= 57; the exact value remains unresolved in the sources reviewed.",
"relevance_source": "recorded",
"body": "A strength-three ternary covering array with 15 columns must display all \\(3^3=27\\) ordered triples in every choice of three columns. One row supplies one triple for a fixed column choice, so every such array has at least 27 rows.\n\nAvila-George, Torres-Jimenez, Hernandez, and Gonzalez-Hernandez report 57 rows for \\(k=15\\) in Table 2(a) of their 2012 primary paper. Their table labels this value as the best-known solution before their cooperative simulated-annealing experiment and reproduces 57 in the experiment. This gives the sourced upper bound\n\\[\n27\\le \\operatorname{CAN}(3,15,3)\\le57.\n\\]\nThe paper says its arrays were deposited in the Cinvestav Covering Array Repository and verified with a separate tool. The repository now requires access, and the audit recovered no public 57-row payload or nonexistence certificate for 56 rows. The exact value should therefore remain open in TheoremDB.",
"status": "reported",
"evidence_grade": "sourced",
"scope": {
"kind": "bounded",
"statement": "the homogeneous ternary covering-array number CAN(3,15,3)",
"bounds": {
"strength": {
"min": 3,
"max": 3
},
"columns": {
"min": 15,
"max": 15
},
"alphabet_size": {
"min": 3,
"max": 3
}
},
"exhaustive": false
},
"reproduction": {
"schema": "theoremdb-reproduction-v1",
"readiness": "source_only",
"kind": "claim",
"citation": {
"url": "https://doi.org/10.1155/2012/897027",
"locator": "J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6"
},
"missing": [
"source",
"command",
"runtime",
"expected_output"
]
},
"formal_statement": null,
"source": {
"url": "https://doi.org/10.1155/2012/897027",
"locator": "J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6"
},
"models": [],
"relations": [
{
"slug": "R94",
"title": "The completed NIST 80-row array covers every interaction",
"object_type": "claim",
"relation": "supports",
"direction": "incoming"
},
{
"slug": "covering-array-3-15-3",
"title": "covering array 3 15 3",
"object_type": "problem",
"relation": "recorded_for",
"direction": "outgoing"
}
]
}6Provenance
View source, identifiers, and projection details
- Project
- covering-array-3-15-3
- Locator
- J. Avila-George, J. Torres-Jimenez, V. Hernandez, and N. Gonzalez-Hernandez, New Bounds for Ternary Covering Arrays Using a Parallel Simulated Annealing, Mathematical Problems in Engineering 2012, Article 897027, Table 2(a), row t=3 and k=15; repository and verification statement in Section 6
- License
- CC0-1.0
- Contributors
- TheoremDB entry research, 2026-07-25
- Source
- doi.org ↗
- Public record
- R95
- Stable alias
- ca3153-claim-published-interval
- Projection
- Reproduction fields are derived from the immutable record.
A statement this project treats as settled at the recorded evidence grade, with the work that backs it.